1. Field of the Invention
The present invention relates generally to a method for adapting wireless telecommunication systems to be compatible with multiple access telecommunication systems.
2. Description of the Related Art
In message systems having a message transmission path between a message source and a message destination transmission and reception devices are employed for message processing and transmission, whereby
1) the message processing and message transmission can ensue in a preferred transmission direction (which is referred to as simplex mode) or in both transmission directions (which is referred to as duplex mode);
2) the message processing is analog or digital;
3) the message transmission via the long distance transmission path is wire-bound or ensues on the basis of various message transmission methods FDMA (frequency division multiple access), TDMA (time division multiple access) and/or CDMA (code division multiplex access)xe2x80x94for example, according to radio standards such as DECT, GSM, WACS or PACS, IS-54, IS-95, PHS, PDC, etc. [See IEEE Communications Magazine, January 1995, pages 50 through 57; D. D. Falconer et al, xe2x80x9cTime Division Multiple Access Methods for Wireless Personal Communicationsxe2x80x9d], ensuing, namely, wirelessly (for example, by radio transmission).
In the context of the present application, the term xe2x80x9cMessagexe2x80x9d is a higher-ranking term that stands both for the content (information) as well as for the physical representation (signal of the communication). Despite the same content of a messagexe2x80x94i.e., the same informationxe2x80x94different signal forms can occur. Thus, for example, a message relating to a given subject matter can be transmitted
(1) in the form of an image,
(2) as a spoken word message,
(3) as a written wordy message or,
(4) as an encrypted word or image.
The transmission type according to (1) . . . (3) above is thereby normally characterized by continuous (analog) signals, whereas discontinuous signals (for example, pulses, digital signals) generally arise in the transmission type according to (4).
Proceeding on the basis of this general definition of a message system, present the invention is directed to a wireless telecommunication system having CDMA, FDMA and TDMA multiple access components, particularly a xe2x80x9cJD-CDMAxe2x80x9d developed communication system that is hybrid with respect to multiple access methods.
In view of a universal mobile telecommunication system (UMTS), wireless telecommunication systems with CDMA, FDMA and TDMA multiple access components, particularly xe2x80x9cJD-CDMAxe2x80x9d telecommunication systems that are hybrid with respect to multiple access methods are referred to as the future radio telecommunication scenario of the third generation according to the publications (1): Nachrichtentechnik Elektronik, Berlin 45, 1995, No. 1, pages 10 through 14 and No. 2, pages 24 through 27, P. Jung, B. Steiner, xe2x80x9cKonzept eines CDMA-Mobilfunksystems mit gemeinsamer Detektion fxc3xcr die dritte Mobilfunkgenerationxe2x80x9d; (2): Nachrichtentechnik Elektronik, Berlin 41, 1991, No. 6, pages 223 through 227 and page 234, P. W. Baier, P. Jung, A. Klein: xe2x80x9cCDMAxe2x80x94ein gxc3xcnstiges Vielfachzugriffsverfahren fxc3xcr frequenzeselektive and zeitvariante Mobilfunkkanxc3xa4lexe2x80x9d; (3): IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Vol. E79-A, No. 12, December 1996, pages 1930 through 1937; P. W. Baier, P. Jung: xe2x80x9cCDMA Myths and Realities Revisitedxe2x80x9d; (4): IEEE Personal Communications, February 1995, Pages 38 through 47; A. Urie, M. Streeton, C. Mourot: xe2x80x9cAn Advanced TDMA Mobile Access System for UMTSxe2x80x9d; (5): Telekom Praxis, 5/1995, Pages 9 through 14, P. W. Baier: xe2x80x9cSpread-Spectrum-Technik and CDMAxe2x80x94eine ursprxc3xcnglich militxc3xa4rische Technik erobert den zivilen Bereichxe2x80x9d; (6): IEEE Personal Communications, February 1995, Pages 48 through 53; P. G. Andermo, L. M. Ewerbring: xe2x80x9cAn CDMA-Based Radio Access Design for UMTSxe2x80x9d; (7): ITG Fachberichte 124 (1993), Berlin, Offenbach: VDE Verlag ISBN 3-8007-1965-7, Pages 67 through 75; Dr. T. Zimmermann, Siemens AG: xe2x80x9cAnwendung von CDMA in der Mobilkommunikationxe2x80x9d.
In the micro-cell or, respectively, macro-cell area of the GSM-specific radio telecommunication system, the radio telecommunication scenario of the second generation is being currently defined (Global System for Mobile Communication; see (1): Informatik Spektrum 14 (1991) June, No. 3, Berlin, DE, A. Mann: xe2x80x9cDer GSM-Standardxe2x80x94Grundlage fxc3xcr digitale europxc3xa4ische Mobilfunknetzexe2x80x9d, Pages 137 through 152; (2): R. Steele: Mobile Radio Communications, Pentech Press, 1992 (Reprint 1994), Chapter 8: The Pan-European Digital Cellular Mobile Radio Systemxe2x80x94known as GSM, Pages 677 ff) and are being defined in the Pico-cell region by the DECT Telecommunication System [digital enhanced (previously: European) cordless telecommunication; see (1): Nachrichtentechnik Elektronik 42 (1992) January/February, No. 1, Berlin, DE, U. Pilger, xe2x80x9cStruktur des DECT-Standardsxe2x80x9d, Pages 23 through 29 in conjunction with ETSI Publication ETS 300175-1 . . . 9, October 1992; (2): Telcom Report 16 (1993), No. 1, J. H. Koch: xe2x80x9cDigitaler Komfort fxc3xcr schnurlose Telekommunikationxe2x80x94DECT-Standard erxc3x6ffnet neue Nutzungsgebietexe2x80x9d, Pages 26 and 27; (3): tec 2/93xe2x80x94the technical magazine of Ascom, xe2x80x9cWege zur universellen mobilen Telekommunikationxe2x80x9d, Pages 35 through 42; (4): Philips Telecommunication Review, Vol. 49, No. 3, September 1991, R. J. Mulder: xe2x80x9cDECT, a universal cordless access systemxe2x80x9d; (5): WO 93/21719 (FIGS. 1 through 3 with appertaining description)].
FIG. 1 shows the TDMA frame and TDMA time slot structure of the GSM mobile radio telephone concept known from the publications (1): Informatik Spektrum 14 (1991) June, No. 3, Berlin, DE, A. Mann: xe2x80x9cDer GSM-Standardxe2x80x94Grundlage fxc3xcr digitale europxc3xa4ische Mobilfunknetzexe2x80x9d, Pages 137 through 152; (2): R. Steele: Mobile Radio Communications, Pentech Press, 1992 (Reprint 1994), Chapter 8: The Pan-European Digital Cellular Mobile Radio Systemxe2x80x94known as GSM, Pages 677 ff).
FIG. 2 shows a multiple access in the uplink (transmission direction xe2x80x9cMobile Partxe2x86x92abase stationxe2x80x9d) from the publication Nachrichtentechnik Elektronik, Berlin 45, 1995, No. 1, Pages 10 through 14 and No. 2, Pages 24 through 27, P. Jung, B. Steiner, xe2x80x9cKonzept eines CDMA-Mobilfunksystems mit gemeinsamer Detektion fxc3xcr die dritte Mobilfunkgenerationxe2x80x9d, which is particularly shown in FIG. 4 of this publicationxe2x80x94standing for the plurality of wireless telecommunication systems with CDMA, FDMA and TDMA multiple access componentsxe2x80x94of a joint detection CDMA mobile radio concept.
For example, the plurality of subscribers simultaneously active in a time slot is K=8.
FIG. 3, proceeding from the illustration of the multiple access in FIG. 2, shows the time slot structure (burst structure) of the uplink (transmission direction xe2x80x9cmobile partxe2x86x92base stationxe2x80x9d) of the joint detection CDMA mobile radio concept that is known from the publication Konzept eines CDMA-Mobilfunksystems mit gemeinsamer Detektion fxc3xcr die dritte Mobilfunkgenerationxe2x80x9d, being particularly shown in FIG. 5 of this publication.
The 24 data symbols of the payload data blocks indicated in FIG. 3 are spread with a subscriber-specific spread code having a spread factor of Q=14, so that each data symbol contains 14 data elements fashioned as xe2x80x9cchipxe2x80x9d.
The object underlying the present invention is comprised in adapting a wireless telecommunication system with a CDMA, FDMA and TDMA multiple access component, particularly what is a hybrid xe2x80x9cJD-CDMAxe2x80x9d telecommunication system with respect to multiple access methods compatibly to a GSM-specific/DECT-specific (micro-cell, macro-cell and/or Pico-cell-specific) telecommunication system with respect to the air interface.
As a result thereof, it is possible, on the one hand, to accept system components that have been hitherto successfully employed in GSM products/DECT products (micro-cell, macro-cell, and/or Pico cell-specific products) of the second mobile radio telephone/cordless telecommunication generation in future wireless telecommunication systems as well with CDMA, FDMA and TDMA multiple access components of the third mobile radio telephone/cordless telecommunication generation without involved modifications, and, on the other hand, to increase the acceptance by the network operators of the second mobile radio telephone/cordless telecommunication generation for a scenario of the third mobile radio telephone/cordless telecommunication generation designed in this way, in that the network operators can profit from the experience they have collected from the second mobile radio telephone/cordless telecommunication generation and can use this experience in a sliding transition to the universal mobile telecommunication system.
According to a first embodiment of the invention which provides a wireless telephone communication system with a CDMA, FDMA and TDMA multiple access component, particularly a hybrid xe2x80x9cJD-CDMAxe2x80x9d telecommunication system with respect to multiple access methods, having the following features:
(a) frequencies of frequency bands predetermined for the wireless telecommunication system are respectively subdivided into a plurality of time slots having a respectively predetermined time slot duration;
(b) respective telecommunication connections from a predetermined plurality of telecommunication subscribers can be simultaneously produced in the frequency bands of the wireless telecommunication system;
(c) the time slots respectively comprise a time slot structure having two payload data blocksxe2x80x94a first payload data block and a second payload data block, a training data block arranged between the payload data blocks and fashioned as xe2x80x9cmidamblexe2x80x9d and a safe time zone arranged following training data block and one of the payload data blocks;
(d) a plurality of first data elements fashioned as a xe2x80x9cchipxe2x80x9d are respectively contained in the payload data blocks and the training data block;
(e) second data elements fashioned as a xe2x80x9cstealing flagxe2x80x9d for signaling purposes are arranged such between at least one of the payload data blocks and the training data block that the ration of the plurality of the data elements arranged before the training data block to the plurality of data elements arranged following the training data block is unequal to one; the idea underlying the invention is comprised, on the one hand, in arranging signaling information fashioned as a xe2x80x9cstealing flagxe2x80x9d for distinguishing between payload (or user information) and signaling channels in the provided time slot structure such that an asymmetrical distribution of time slots arises with respect to a training data block (as so called midamble) of the time slot structure. According to further embodiments in which the second data elements are arranged before the training data block, alternately, the second data elements are arranged after the training data block, or the second data elements are arranged in equal parts before and following the training data block; it is thereby particularly advantageous when the signaling information are placed immediately before and/or after the training data block for protection against time variance.
According to another embodiment which provides a wireless telephone communication system with a CDMA, FDMA and TDMA multiple access component, particularly a hybrid xe2x80x9cJD-CDMAxe2x80x9d telecommunication system with respect to multiple access methods, having the following features:
(a) frequencies of frequency bands predetermined for the wireless telecommunication system are respectively subdivided into a plurality of time slots having a respectively predetermined time slot duration;
(b) respective telecommunication connections from a predetermined plurality of telecommunication subscribers can be simultaneously produced in the frequency bands of the wireless telecommunication system;
(c) the time slots respectively comprise a time slot structure with two payload data blocksxe2x80x94a first payload data block and a second payload data block, a training data block arranged between the payload data blocks and fashioned as a xe2x80x9cmidamblexe2x80x9d, signaling data fashioned as a xe2x80x9cstealing flagxe2x80x9d, and a safe time zone arranged following the training data block, the signaling data block and one of the payload data blocks;
(d) a plurality of first data elements fashioned as a xe2x80x9cchipxe2x80x9d are respectively contained in the payload data blocks and the training data block;
(e) the signaling data contain a plurality of second data elements;
(f) the transmission time duration of the data element amounts to a multiple of a predetermined, particularly GSM-specific clock frequency covering the numerical range from 5 through 7.
With the development of the invention yet another embodiment, wherein the frequencies of the frequency band are respectively subdivided into eight time slots each having a respectively predetermined time slot duration of approximately 577 xcexcs; the wireless telecommunication system with a CDMA, FDMA and TDMA multiple access component is (also) adapted to the GSM telecommunication system with respect to the time slot duration.
The development according to a further embodiment, wherein the first data elements are contained in first data symbols spread with a telecommunication subscriber-specific spread code having a spread factor of essentially 14 proves advantageous in view of the development according to claim 3 because the combination of the foregoing embodiment with telecommunication connections of essentially eight telecommunication subscribers which can be simultaneously produced in the frequency band of the wireless telecommunication system the foregoing and 4 yields a xe2x80x9c8xc3x978 checkerboard patternxe2x80x9d, whereby the information (for example, GSM information) to be transmitted canxe2x80x94completely equivalentlyxe2x80x94be packed either in a CDMA code or in a time slot. Over and above this, such a combination is advantageous in the transmission of ISDN information via the air interface of the wireless telecommunication system with a CDMA-FDMA and TDMA multiplex access component.
Further advantageous developments of the invention are provided as well by an embodiment having the second data elements contained in second data symbols spread with a telecommunication subscriber-specific spread code having a spread factor of essentially 14. Preferably, the second data symbols are fashioned as the signaling data. Essentially 33 first data symbols are respectively contained in the payload data blocks. In one embodiment, the data symbols respectively contain two gross bits. The payload data transmission rate amounts to essentially 13 kBit/s given an interleaving depth of xe2x80x9c4xe2x80x9d and a convolution code having a code rate xe2x80x9c0.5xe2x80x9d and a constraint length of xe2x80x9c5xe2x80x9d. Essentially xe2x80x9c243xe2x80x9d first data elements may be contained in the training data block. The safe time zone of one embodiment is of a time duration of at least 30 xcexcs.
FIG. 1 is a diagram of a TDMA Frame known in the art.
FIG. 2 is a diagram of a multiple access in the uplink known in the art.
FIG. 3 is another diagram of the multiple access of FIG. 2 illustrating the time slot structure of the uplink.
FIG. 4 is a diagram of a time slot structure of a wireless telecommunication system according to the invention.